:root {
  --color-surface: #eeeded;
  --color-surface-alt: #e6e4e4;
  --color-surface-deep: #dad8d8;
  --color-ink: #483e3d;
  --color-ink-soft: #706361;
  --color-ink-muted: #877a78;
  --color-line: #d0cecd;
  --color-primary: #cb4634;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #e9d6d3;
  --color-accent: #db361f;
  --color-accent-ink: #ffffff;
  --color-highlight: #ebccc8;
  --color-focus: #cb2710;
  --color-contrast-surface: #2b1b19;
  --color-contrast-ink: #e7e5e4;
  --color-contrast-line: #544746;
  --color-contrast-accent: #e45743;
  --overlay-scrim: linear-gradient(180deg, rgba(43, 27, 25, 0.35) 0%, rgba(43, 27, 25, 0.72) 55%, rgba(43, 27, 25, 0.92) 100%);
  --font-heading: "Kaiti SC", STKaiti, KaiTi, "Songti SC", serif;
  --font-body: "Songti SC", "PingFang SC", "Microsoft YaHei", serif;
  --font-mono: ui-monospace, Menlo, Consolas, monospace;
  --text-xs: 11.0px;
  --text-sm: 14.7px;
  --text-base: 17px;
  --text-lg: 22.7px;
  --text-xl: 30.2px;
  --text-2xl: 40.3px;
  --text-3xl: 53.7px;
  --text-4xl: 71.5px;
  --text-display: clamp(38px, 7.8vw, 100px);
  --text-figure: clamp(32px, 5.6vw, 72px);
  --weight-heading: 534;
  --weight-body: 400;
  --leading-body: 2.0;
  --leading-heading: 1.27;
  --tracking-heading: 0.016em;
  --radius-sm: 1px;
  --radius-md: 2px;
  --radius-lg: 2px;
  --radius-pill: 2px;
  --border-thin: 1px;
  --border-thick: 1px;
  --shadow-1: none;
  --shadow-2: none;
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --container: 1000px;
  --measure: 58ch;
  --gutter: 32px;
  --section-y: 104px;
  --section-y-lg: 146px;
}

/* ============ reset ============ */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
}

body {
  margin: 0;
  background-color: var(--color-surface);
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-body);
  line-height: var(--leading-body);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* 纸面墨色浓淡层：不使用彩色分区，只用纸色深浅 */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image:
    radial-gradient(64% 44% at 10% 4%, color-mix(in srgb, var(--color-surface-alt) 94%, transparent) 0%, transparent 72%),
    radial-gradient(58% 48% at 92% 90%, color-mix(in srgb, var(--color-surface-deep) 78%, transparent) 0%, transparent 74%);
}

img, svg, video { display: block; max-width: 100%; height: auto; }

h1, h2, h3, h4, h5, h6, p, figure, blockquote, dl, dd, hr { margin: 0; }

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

button {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  padding: 0;
}

a { color: inherit; }

:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

#main-content { display: block; scroll-margin-top: var(--space-6); }

main { position: relative; z-index: 1; }

/* ============ 布局工具 ============ */
.shell {
  width: min(100% - (var(--space-3) * 2), var(--container));
  margin-inline: auto;
}

.section { padding-block: var(--section-y); }
.section--lg { padding-block: var(--section-y-lg); }
.section--tight { padding-block: var(--space-8); }

.section--alt { background-color: var(--color-surface-alt); }

.section--deep {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}
.section--deep h1,
.section--deep h2,
.section--deep h3,
.section--deep h4 { color: var(--color-contrast-ink); }
.section--deep .eyebrow,
.section--deep .meta-line { color: color-mix(in srgb, var(--color-contrast-ink) 58%, transparent); }

.rule {
  height: var(--border-thin);
  border: 0;
  background-color: var(--color-line);
}

.grid { display: grid; gap: var(--space-4); }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.grid--split { grid-template-columns: minmax(0, 7fr) minmax(0, 5fr); }

.stack > * + * { margin-top: var(--space-3); }

.measure { max-width: var(--measure); }

.prose {
  max-width: var(--measure);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink);
}
.prose > * + * { margin-top: var(--space-3); }
.prose h2 { font-size: var(--text-xl); margin-top: var(--space-6); }
.prose h3 { font-size: var(--text-lg); margin-top: var(--space-4); }
.prose ul, .prose ol { padding-left: 1.4em; }
.prose ul li, .prose ol li { margin-top: var(--space-1); }

/* ============ 排版组件 ============ */
.eyebrow {
  display: inline-block;
  font-family: var(--font-body);
  font-size: var(--text-xs);
  letter-spacing: 0.36em;
  text-indent: 0.36em;
  color: var(--color-ink-muted);
  line-height: 1.8;
}

.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--space-1) var(--space-4);
  padding-bottom: var(--space-2);
  border-bottom: var(--border-thin) solid var(--color-line);
  margin-bottom: var(--space-6);
}

.section-title {
  font-size: var(--text-2xl);
  line-height: var(--leading-heading);
  margin: 0;
}

.lead {
  font-size: var(--text-lg);
  line-height: 1.9;
  color: var(--color-ink-soft);
  max-width: var(--measure);
}

.meta-line {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-ink-muted);
  line-height: 1.9;
}

img, svg, video { display: block; max-width: 100%; height: auto; }

h1, h2, h3, h4, h5, h6, p, figure, blockquote, ul, ol, dl, dd, hr { margin: 0; }

ul, ol { padding: 0; }
ul[class], ol[class] { list-style: none; }

a { color: inherit; }

button { font: inherit; color: inherit; background: none; border: 0; padding: 0; cursor: pointer; }

/* 无障碍：键盘焦点环 */
:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* 纸面保底：主区域在渲染层之上 */
.site-header,
.site-main,
.site-footer { position: relative; z-index: 1; }

/* ============ 布局骨架 ============ */
.shell {
  width: min(100% - (var(--space-3) * 2), var(--container));
  margin-inline: auto;
}

.section { padding-block: var(--section-y); }
.section--lg { padding-block: var(--section-y-lg); }
.section--tight { padding-block: var(--space-8); }

.section--alt {
  background-color: var(--color-surface-alt);
  border-block: var(--border-thin) solid var(--color-line);
}

.section--deep {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}
.section--deep .section-title,
.section--deep .prose,
.section--deep .lead { color: var(--color-contrast-ink); }
.section--deep .lead { color: color-mix(in srgb, var(--color-contrast-ink) 78%, transparent); }

.rule {
  height: var(--border-thin);
  border: 0;
  background-color: var(--color-line);
}

.grid { display: grid; gap: var(--space-4); }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.grid--split { grid-template-columns: minmax(0, 7fr) minmax(0, 5fr); }

.stack > * + * { margin-top: var(--space-3); }

.measure { max-width: var(--measure); }

.prose {
  max-width: var(--measure);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink);
}
.prose > * + * { margin-top: var(--space-3); }
.prose h2 { font-size: var(--text-xl); margin-top: var(--space-6); }
.prose h3 { font-size: var(--text-lg); margin-top: var(--space-4); }
.prose ul,
.prose ol { padding-left: 1.4em; list-style: disc; }
.prose li + li { margin-top: var(--space-1); }
.prose a {
  text-decoration: none;
  border-bottom: var(--border-thin) solid var(--color-primary);
  color: color-mix(in srgb, var(--color-primary) 88%, var(--color-ink));
}
.prose a:hover { border-bottom-width: 2px; }

.eyebrow {
  display: inline-block;
  font-family: var(--font-body);
  font-size: var(--text-xs);
  letter-spacing: 0.34em;
  text-indent: 0.34em;
  color: var(--color-ink-muted);
  line-height: 1.8;
}

.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--space-1) var(--space-4);
  padding-bottom: var(--space-2);
  border-bottom: var(--border-thin) solid var(--color-line);
  margin-bottom: var(--space-6);
}

.section-title {
  font-size: var(--text-2xl);
  line-height: var(--leading-heading);
}

.lead {
  font-size: var(--text-lg);
  line-height: 1.9;
  color: var(--color-ink-soft);
  max-width: var(--measure);
}

.meta-line {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
  line-height: 1.9;
}

/* ============ 标签 · 徽标 ============ */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 0.35em;
  padding: 2px 8px;
  border: var(--border-thin) solid var(--color-line);
  background-color: var(--color-surface-deep);
  border-radius: var(--radius-sm);
  font-family: var(--font-body);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  line-height: 1.7;
  color: var(--color-ink-soft);
  text-decoration: none;
  white-space: nowrap;
}

.tag--primary {
  background-color: var(--color-primary-soft);
  border-color: color-mix(in srgb, var(--color-primary) 52%, transparent);
  color: color-mix(in srgb, var(--color-primary) 88%, var(--color-ink));
}

.tag--ink {
  background-color: var(--color-contrast-surface);
  border-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}

/* ============ 资料卡 ============ */
.card {
  background-color: var(--color-surface-alt);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
  padding: var(--space-4);
}

.card--flat {
  background-color: transparent;
  border-color: transparent;
  padding: 0;
}

.card--deep {
  background-color: var(--color-contrast-surface);
  border-color: var(--color-contrast-line);
  color: var(--color-contrast-ink);
}
.card--deep .card-title { color: var(--color-contrast-ink); }

.card-head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2);
  margin-bottom: var(--space-2);
}

.card-title {
  font-size: var(--text-lg);
  line-height: var(--leading-heading);
}

/* ============ 数据锚点 ============ */
.data-cell {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  padding-left: var(--space-3);
  border-left: var(--border-thin) solid var(--color-line);
}

.data-key {
  font-size: var(--text-xs);
  letter-spacing: 0.22em;
  color: var(--color-ink-muted);
  line-height: 1.8;
}

.data-value {
  font-family: var(--font-mono);
  font-size: var(--text-xl);
  line-height: 1.15;
  letter-spacing: -0.01em;
  color: var(--color-ink);
  font-variant-numeric: tabular-nums;
}

.data-value--accent { color: var(--color-accent); }

.figure-display {
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: 400;
  line-height: 1;
  letter-spacing: -0.015em;
  color: var(--color-ink);
  font-variant-numeric: tabular-nums;
}

.figure-display--accent { color: var(--color-accent); }

/* ============ 按钮 ============ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-1);
  padding: 10px 22px;
  border: var(--border-thin) solid var(--color-ink);
  border-radius: var(--radius-sm);
  background-color: transparent;
  color: var(--color-ink);
  font-family: var(--font-heading);
  font-size: var(--text-base);
  letter-spacing: 0.08em;
  line-height: 1.6;
  text-decoration: none;
  transition: background-color 160ms ease, color 160ms ease, border-color 160ms ease;
}

.btn:hover {
  background-color: var(--color-contrast-surface);
  border-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}

.btn--primary {
  background-color: var(--color-primary);
  border-color: var(--color-primary);
  color: var(--color-primary-ink);
}

.btn--primary:hover {
  background-color: color-mix(in srgb, var(--color-primary) 82%, var(--color-contrast-surface));
  border-color: color-mix(in srgb, var(--color-primary) 82%, var(--color-contrast-surface));
  color: var(--color-primary-ink);
}

.btn--ghost {
  border-color: var(--color-line);
  background-color: var(--color-surface-alt);
  color: var(--color-ink-soft);
  font-family: var(--font-body);
  font-size: var(--text-sm);
}

.btn--ghost:hover {
  background-color: var(--color-surface-deep);
  border-color: var(--color-ink-muted);
  color: var(--color-ink);
}

/* ============ 面包屑 ============ */
.breadcrumb {
  padding-block: var(--space-3);
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
}

.breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
  list-style: none;
  margin: 0;
  padding: 0;
}

.breadcrumb-list li {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
}

.breadcrumb-list li + li::before {
  content: "/";
  color: var(--color-line);
}

.breadcrumb-list a {
  color: var(--color-ink-soft);
  text-decoration: none;
  border-bottom: var(--border-thin) solid transparent;
  transition: color 160ms ease, border-color 160ms ease;
}

.breadcrumb-list a:hover {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

/* ============ 锚点导航（长页索引） ============ */
.anchor-nav {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  list-style: none;
  margin: 0;
  padding: 0;
}

.anchor-nav a {
  display: inline-block;
  padding: 6px 12px;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  background-color: var(--color-surface-alt);
  color: var(--color-ink-soft);
  font-size: var(--text-sm);
  line-height: 1.7;
  letter-spacing: 0.06em;
  text-decoration: none;
  transition: background-color 160ms ease, color 160ms ease, border-color 160ms ease;
}

.anchor-nav a:hover {
  background-color: var(--color-surface-deep);
  color: var(--color-ink);
}

.anchor-nav a.is-active {
  background-color: var(--color-primary-soft);
  border-color: color-mix(in srgb, var(--color-primary) 50%, transparent);
  color: color-mix(in srgb, var(--color-primary) 88%, var(--color-ink));
}

/* ============ 图片容器（页面阶段放占位图） ============ */
.media {
  position: relative;
  display: block;
  overflow: hidden;
  background-color: var(--color-surface-deep);
  border-radius: 0;
}

.media > img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media--16x9 { aspect-ratio: 16 / 9; }
.media--4x3 { aspect-ratio: 4 / 3; }
.media--1x1 { aspect-ratio: 1 / 1; }
.media--tall { aspect-ratio: 3 / 4; }

.media-grid {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(90deg, rgba(231, 229, 228, 0.16) var(--border-thin), transparent var(--border-thin)),
    linear-gradient(180deg, rgba(231, 229, 228, 0.16) var(--border-thin), transparent var(--border-thin));
  background-size: 16.6667% 25%;
}

.media-caption {
  position: absolute;
  inset-inline: 0;
  inset-block-end: 0;
  padding: var(--space-3);
  background-image: var(--overlay-scrim);
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
  line-height: 1.8;
}

.media-tag {
  position: absolute;
  inset-block-start: var(--space-2);
  inset-inline-start: var(--space-2);
}

/* ============ 头部 ============ */
.site-header {
  position: relative;
  z-index: 30;
  background-color: var(--color-surface-alt);
  border-bottom: var(--border-thin) solid var(--color-ink);
}

.skip-link {
  position: absolute;
  inset-inline-start: var(--space-3);
  inset-block-start: -80px;
  z-index: 90;
  padding: 10px 18px;
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  text-decoration: none;
  border-radius: var(--radius-sm);
  transition: inset-block-start 160ms ease;
}

.skip-link:focus {
  inset-block-start: var(--space-2);
}

.scroll-progress {
  position: fixed;
  inset-block-start: 0;
  inset-inline-start: 0;
  width: 100%;
  height: 2px;
  z-index: 60;
  pointer-events: none;
  background-color: transparent;
}

.scroll-progress span {
  display: block;
  width: 0;
  height: 100%;
  background-color: var(--color-primary);
  opacity: 0;
  transition: opacity 160ms ease;
}

.scroll-progress[data-active="true"] span { opacity: 1; }

.header-frame {
  position: relative;
  display: block;
}

.header-top {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2) var(--space-4);
  padding-block: var(--space-3);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  text-decoration: none;
}

.brand-mark {
  display: grid;
  place-items: center;
  inline-size: 40px;
  block-size: 40px;
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  line-height: 1;
  border-radius: var(--radius-sm);
}

.brand-text { display: block; }

.brand-name {
  display: block;
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: var(--weight-heading);
  line-height: 1.15;
  letter-spacing: 0.12em;
  color: var(--color-ink);
}

.brand-note {
  display: block;
  margin-top: 2px;
  font-size: var(--text-xs);
  letter-spacing: 0.24em;
  color: var(--color-ink-muted);
}

.header-utility {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1) var(--space-3);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
}

.utility-item {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  white-space: nowrap;
}

.utility-item + .utility-item::before {
  content: "";
  display: inline-block;
  inline-size: var(--border-thin);
  block-size: 12px;
  margin-inline-end: var(--space-2);
  background-color: var(--color-line);
}

.utility-key {
  font-size: var(--text-xs);
  letter-spacing: 0.2em;
  color: var(--color-ink-muted);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-1);
  padding: 8px 12px;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  background-color: var(--color-surface);
  color: var(--color-ink);
  font-size: var(--text-sm);
  letter-spacing: 0.12em;
  transition: background-color 160ms ease, border-color 160ms ease;
}

.nav-toggle:hover {
  background-color: var(--color-surface-deep);
  border-color: var(--color-ink-muted);
}

.nav-toggle-bars {
  display: grid;
  gap: 3px;
  inline-size: 16px;
}

.nav-toggle-bars span {
  display: block;
  block-size: var(--border-thin);
  background-color: currentColor;
}

.nav-toggle-bars span:nth-child(2) { inline-size: 72%; }

.site-nav {
  border-top: var(--border-thin) solid var(--color-line);
}

.nav-list {
  display: flex;
  flex-wrap: wrap;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-list > li + li {
  border-left: var(--border-thin) solid var(--color-line);
}

.nav-link {
  display: block;
  padding: var(--space-2) var(--space-3) calc(var(--space-2) + 1px);
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  line-height: 1.4;
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
  text-decoration: none;
  box-shadow: inset 0 -2px 0 transparent;
  transition: background-color 160ms ease, color 160ms ease, box-shadow 160ms ease;
}

.nav-list > li:first-child .nav-link { padding-inline-start: 0; }

.nav-link:hover {
  background-color: var(--color-surface-deep);
  box-shadow: inset 0 -2px 0 var(--color-primary);
}

.nav-link[aria-current="page"] {
  color: var(--color-primary);
  background-color: var(--color-primary-soft);
  box-shadow: inset 0 -2px 0 var(--color-primary);
}

/* ============ 页脚 ============ */
.site-footer {
  position: relative;
  z-index: 1;
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-top: var(--border-thin) solid var(--color-contrast-line);
}

.footer-shell {
  padding-block: var(--space-8) var(--space-6);
}

.footer-upper {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.4fr) minmax(0, 1.1fr);
  gap: var(--space-6);
  padding-bottom: var(--space-6);
  border-bottom: var(--border-thin) solid var(--color-contrast-line);
}

.footer-brand-name {
  font-family: var(--font-heading);
  font-size: var(--text-2xl);
  font-weight: var(--weight-heading);
  line-height: 1.2;
  letter-spacing: 0.12em;
  color: var(--color-contrast-ink);
}

.footer-brand-note {
  margin-top: var(--space-1);
  font-size: var(--text-sm);
  letter-spacing: 0.16em;
  color: color-mix(in srgb, var(--color-contrast-ink) 62%, transparent);
}

.footer-brand-line {
  margin-top: var(--space-3);
  padding-inline-start: var(--space-2);
  border-inline-start: 2px solid var(--color-contrast-accent);
  max-width: 34ch;
  font-size: var(--text-sm);
  line-height: 1.9;
  color: color-mix(in srgb, var(--color-contrast-ink) 76%, transparent);
}

.footer-heading {
  margin-bottom: var(--space-2);
  font-size: var(--text-xs);
  letter-spacing: 0.32em;
  color: color-mix(in srgb, var(--color-contrast-ink) 55%, transparent);
}

.footer-index {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 var(--space-4);
  list-style: none;
  margin: 0;
  padding: 0;
}

.footer-index a {
  display: block;
  padding-block: var(--space-1);
  border-bottom: var(--border-thin) solid var(--color-contrast-line);
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
  line-height: 1.9;
  text-decoration: none;
  transition: color 160ms ease, padding-inline-start 160ms ease;
}

.footer-index a:hover {
  color: var(--color-contrast-accent);
  padding-inline-start: 6px;
}

.footer-contact-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.footer-contact-list li {
  display: grid;
  grid-template-columns: 3.6em minmax(0, 1fr);
  gap: var(--space-2);
  padding-block: var(--space-1);
  border-bottom: var(--border-thin) solid var(--color-contrast-line);
  font-size: var(--text-sm);
}

.contact-key {
  padding-top: 4px;
  font-size: var(--text-xs);
  letter-spacing: 0.2em;
  color: color-mix(in srgb, var(--color-contrast-ink) 55%, transparent);
}

.contact-value {
  line-height: 1.8;
  color: var(--color-contrast-ink);
  word-break: break-word;
}

.footer-lower {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  padding-top: var(--space-4);
}

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  list-style: none;
  margin: 0;
  padding: 0;
}

.footer-legal a {
  color: color-mix(in srgb, var(--color-contrast-ink) 82%, transparent);
  font-size: var(--text-sm);
  text-decoration: none;
  border-bottom: var(--border-thin) solid transparent;
  transition: color 160ms ease, border-color 160ms ease;
}

.footer-legal a:hover {
  color: var(--color-contrast-ink);
  border-bottom-color: var(--color-contrast-accent);
}

.footer-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: color-mix(in srgb, var(--color-contrast-ink) 62%, transparent);
}

.footer-sep { color: var(--color-contrast-line); }

/* ============ 响应式 ============ */
@media (max-width: 980px) {
  .grid--3,
  .grid--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .grid--split { grid-template-columns: minmax(0, 1fr); }

  .footer-upper {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: var(--space-4);
  }
  .footer-brand { grid-column: 1 / -1; }
}

@media (max-width: 860px) {
  .header-utility { display: none; }
  .nav-toggle { display: inline-flex; }

  .site-nav {
    display: none;
    border-top: var(--border-thin) solid var(--color-line);
  }
  .site-nav[data-open] { display: block; }

  .nav-list {
    flex-direction: column;
    padding-block: var(--space-1);
  }
  .nav-list > li + li {
    border-left: 0;
    border-top: var(--border-thin) solid var(--color-line);
  }
  .nav-link {
    padding: var(--space-2) 0;
    font-size: var(--text-base);
  }
  .nav-list > li:first-child .nav-link { padding-inline-start: 0; }
}

@media (max-width: 640px) {
  .grid--2,
  .grid--3,
  .grid--4 { grid-template-columns: minmax(0, 1fr); }

  .footer-upper { grid-template-columns: minmax(0, 1fr); }
  .footer-index { grid-template-columns: minmax(0, 1fr); }
  .footer-lower { flex-direction: column; align-items: flex-start; }

  .brand-mark { inline-size: 34px; block-size: 34px; font-size: var(--text-base); }
  .brand-name { font-size: var(--text-lg); }
  .brand-note { letter-spacing: 0.16em; }
}

/* ============ 动效偏好 ============ */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
  .scroll-progress span { transition: none; }
}